A typical form of manually actuable blind riveting tool comprises a tool housing with a front sleeve or tube which is disposed at the front end of the tool housing and the front end of which carries a mouthpiece member for receiving a pulling mandrel of a rivet. A collet for clamping the pulling mandrel is disposed in the front sleeve or tube member, behind the mouthpiece member and is connected to a movable pulling plunger which extends through the tool housing and which is in the form of a discharge passage for mandrels which have been pulled off. The tool further has two pivotal levers which are mounted laterally on the tool housing, for transmitting an axial force to the pulling mandrel, for the production of a stroke movement during the actual riveting operation.
With such a tool therefore, to carry out a riveting operation, the two levers must first be moved entirely into the fully open position in which they are pivoted away from the tool housing to the greatest possible extent. By virtue of that movement, the pulling plunger is moved forwardly in the tool housing and the clamping collect is opened by virtue of positive co-operation thereof with the mouthpiece member which is of a complementary configuration, so that the pulling mandrel of the blind rivet to be set can then be inserted into the mouthpiece member. The two pivotal levers are then firstly moved towards the closed position again until the pulling mandrel is gripped by the clamping collet as it slides rearwardly in the tool housing. In the actual riveting operation which is now effected, the two pivotal levers are further pressed inwardly towards the tool housing so that an axial force component is applied to the pulling mandrel of the rivet by way of the pulling plunger. As a result, the pulling mandrel breaks off at a predetermined desired-rupture location, thereby forming the rivet setting head.
As the angle to which the pivotal levers having to be opened to carry out the actual riveting step increases with increasing pulling mandrel diameter, in such a blind riveting tool the force required for setting a rivet increases with the size and strength of the blind rivet to be set.
The usual practice in dealing with that problem is to use a set of different blind riveting tools which are adapted to the respective rivet dimensions involved. It is also possible to use blind riveting tools which have an interchangeable front sleeve or tube member, with the amount of force applied to set the rivet being suitably adjusted in dependence on the size and strength of the blind rivet to be set, by using a sleeve or tube member of suitable size.
However, both those situations involve a considerable amount of expenditure on items of equipment as either it is necessary to provide a set of different hand riveting tools, or each hand riveting tool must include a set of for example three or four interchangeable sleeve or tube members of specific sizes and configurations. In addition, in the latter case, interchanging the sleeve or tube members not only takes up a relatively great amount of time, but it is also a nuisance and a burden from the point of view of the operator.